This review summarizes the recent developments of di­sulfide bond formation with a variety of reagents. The scope and limitations of the presented methods are discussed. The syntheses of unsymmetrical disulfides are highlighted in order to present the most versatile achievements. 1 Introduction 2 Preparation of Disulfides 2.1 By Oxidation of Thiols 2.2 By Reductive Coupling of Sulfonyl Chlorides 2.3 By Reaction with Sulfur Monochloride 2.4 By Radical Cyclization of Substituted Aminothiourea Derivatives­ 2.5 Using 1-Chlorobenzotriazole 2.6 From Elemental Sulfur 2.7 From Organophosphorus Sulfenyl Bromide 2.8 From N-Trifluoroacetyl Arenesulfenamides 2.9 Using Phase-Transfer Catalysis 2.10 From a Thiol-Disulfide Exchange Reaction 2.11 From Thiocyanates 2.12 From 2-(Trimethylsilyl)ethyl Sulfides 2.13 From Thiosulfonates and Thiosulfates 2.14 From Thioesters 2.15 By Disulfide Exchange Reactions 2.16 From Tetrathiomolybdate 2.17 By Miscellaneous Reactions 3 Conclusions

Self-assembled monolayers (SAMs) of alkane thiols on gold and other metals are versatile constructs with which to study interfacial phenomena and reactions at surfaces. Surface properties of SAMs - e.g., wettability, stability in diverse environments, propensity to interact with or to resist adsorption of macromolecules -- depend on and can be controlled flexibly by the properties of the functional (head) groups in the w position of the alkyl chain. SAMs provide a basis for many important scientific and technological applications, ranging from micropatterning methods, through sensing, to biological recognition. Despite their importance, the literature on SAMs and the synthesis of molecules that constitute them remains scattered and often conflicting. The purpose of this Review is (i) to summarize the applications and physical properties of SAMs and (ii) to systematize the strategies of synthesis of ω-functionalized alkane thiols. Generic retrosynthetic scheme is developed that allows efficient synthetic planning. Issues related to the selection of appropriate protecting groups and the ways of introduction of the thiol functionality are discussed in detail, and illustrated with examples of syntheses of several complex alkane thiols.